我有一個字典串列：
friends = [
{'name': 'Sam', 'gender': 'male', 'sport': 'Basketball'},
{'name': 'Emily', 'gender': 'female', 'sport': 'volleyball'},
]
我需要創建函式query、select和field_filter來處理類似的串列。這些功能必須提供選擇必要的列并通過這些列進行過濾的可能性。
例子：
result = query(friends,
select('name', 'gender', 'sport'),
field_filter('sport', *('Basketball', 'volleyball')),
field_filter('gender', *('male',)))`
[{'gender': 'male', 'name': 'Sam', 'sport': 'Basketball'}]
我需要使用預定義的代碼：
from typing import Dict, Any, Callable, Iterable
DataType = Iterable[Dict[str, Any]]
ModifierFunc = Callable[[DataType], DataType]
def query(data: DataType, selector: ModifierFunc,
*filters: ModifierFunc) -> DataType:
"""Query data with column selection and filters
:param data: List of dictionaries with columns and values
:param selector: result of `select` function call
:param filters: Any number of results of `field_filter` function calls
:return: Filtered data"""
pass
def select(*columns: str) -> ModifierFunc:
"""Return function that selects only specific columns from dataset"""
pass
def field_filter(column: str, *values: Any) -> ModifierFunc:
"""Return function that filters specific column to be one of `values`"""
pass
uj5u.com熱心網友回復：
盡管這個問題暗示select并且field_filter可能想要成為類，但我認為這里沒有必要；我只是讓他們回傳常規的舊元組：
select = field_filter = lambda *args: args
然后query只是一個串列和字典理解，您可以在其中迭代字典串列并select從匹配field_filters 的字典中回傳 ed 欄位：
def query(data, keys, *filters):
return [
{k: d[k] for k in keys}
for d in data
if all(d[k] in v for k, *v in filters)
]
friends = [
{'name': 'Sam', 'gender': 'male', 'sport': 'Basketball'},
{'name': 'Emily', 'gender': 'female', 'sport': 'volleyball'},
]
result = query(
friends,
select('name', 'gender', 'sport'),
field_filter('sport', *('Basketball', 'volleyball')),
field_filter('gender', *('male',))
)
print(result) # [{'name': 'Sam', 'gender': 'male', 'sport': 'Basketball'}]
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